What was the great upheaval? a. it was a large economic crash in 1879. b. it was a mass movement of african americans from the south to northern cities. c. a deterioration of relations between britain and the united states d. a mass strike that involved workers from different industries and from across the nation

D. A mass strike that involved workers from different industries and from across the nation

the correct answer is:   "   3.6 % " .

          →   the unemployment rate is:   " 3.6 % " .

explanation:

to calculate the "unemployment rate" :

the "unemployment rate"   =

  [# of people unemployed] /   [working age population]   * 100 %   ;

                =   [9 million] / [250 million]     *   100 % ;

    →     note:   the units of "million" cancel out;

                    since:   " {million} / {million} = 1 " ;

                =   (9 / 250)   * 100 %   ;

                = 0.036 * 100 % ;

                =   3.6 %

answer:   the unemployment rate is:   " 3.6 % " .